氧化猪脂-热反应制备猪肉香精研究

以过氧化值、茴香胺值和酸值表征脂肪的氧化状态，采用控制氧化工艺，制备了不同氧化状态的猪脂样品。根据各氧化猪脂的热反应产物感官评价结果，分析比较了氧化猪脂的过氧化值、茴香胺值和酸值对热反应产物风味的影响。初步确定了氧化猪脂-热反应制备猪肉香精的氧化猪脂控制指标：过氧化值230-630meq氧／kg脂肪，p-A．V．大于60，A．V．小于4．0mg KOH／g脂肪。     

猪脂控制氧化及挥发性氧化产物研究

通过单因素试验和正交试验研究以热反应制备肉味香精前体物为目的的猪脂肪控制氧化工艺条件。以过氧化值(POV)、硫代巴比妥酸值(TBA)和酸值(AV)表征油脂的氧化状态。结果表明,猪脂肪控制氧化的较佳工艺条件为：反应温度120℃、反应时间2h、氧气流速0.025m3/h。采用固相微萃取- 气质联用技术对猪脂肪控制氧化产物中的挥发性成分进行分析,共鉴定出32 种化合物,其中醛类化合物占52.52%,为猪脂肪控制氧化产物中的主要挥发性成分。     

猪脂肪控制氧化条件优化研究

研究影响猪脂氧化的因素,确定最佳氧化条件,为美拉德热反应制备肉味香精提供较优前提物质,设计单因素实验与正交试验,通过控制氧化温度、空气流量、氧化时间获得氧化猪脂,并测定氧化猪脂的酸价(AV)、过氧化值(POV)、茴香胺值(P-AV)确定猪脂氧化较优工艺,得出猪脂控制氧化的较优工艺条件是:反应温度120℃,反应时间2h,空气流速0. 4L/min。     

DHA/AA粉末油脂氧化稳定性与特定挥发性氧化产物的比较分析研究

对5种市售DHA/AA粉末油脂在60℃条件下进行了50 d加速氧化实验,检测了加速氧化过程中样品过氧化值、茴香胺值、挥发性氧化产物的含量,并将过氧化值、茴香胺值分别与对应的丙醛、己醛含量进行相关性分析。结果表明,丙醛和己醛是DHA/AA粉末油脂的特征氧化产物,其在氧化过程中的含量与过氧化值、茴香胺值呈显著线性相关。     

鸭脂氧化及其挥发性香气成分气相色谱-质谱分析

以过氧化值、p-茴香胺值、酸值表示鸭脂的氧化状态,通过单因素试验和感官鉴定研究氧化温度和时间对 鸭脂氧化的影响,确定以制备鸭肉香精前体物为目标的鸭脂氧化条件为氧化温度120 ℃、时间4 h。在此条件下,鸭 脂的过氧化值为22.30 meq/kg,p-茴香胺值为7.04,酸值为0.93 mg KOH/g,具有强烈的脂肪香气以及轻微的油炸气 息。通过固相微萃取-气相色谱-质谱分析氧化前后鸭脂的挥发性香气成分,氧化后鸭脂共检测出32 种化合物,与氧化前相 比,种类及含量均有所增加,其中醛类物质11 种,含量为42.29%,其中己醛含量高达29.40%。另外还检测出烃类、呋喃、 醇类、羧酸类等多种呈香化合物,为后期以氧化鸭脂为原料进行Maillard反应制备鸭肉香精的技术开发提供参考。     

葡萄籽油和亚麻籽油储藏期间氧化对功能性成分影响

通过实验研究35℃恒温避光储藏亚麻籽油和葡萄籽油过氧化值、p–茴香胺值、脂肪酸组成和维生素E含量变化,探讨储藏期间油脂氧化劣变对其功能性成分影响。结果表明,经60天储藏,葡萄籽油、亚麻油过氧化值分别达241.30 mmol/kg、248.72 mmol/kg;p–茴香胺值为32.20、104.06;油脂脂肪酸组成不饱和脂肪酸减少0.35%和0.41%,亚油酸和亚麻酸分别降低0.20%和0.09%、0.23%和1.04%,反式脂肪酸含量基本没有变化;维生素E含量显著降低均未检出;储藏期间亚麻籽油氧化对功能性成分影响均大于葡萄籽油。     

调控氧化猪脂影响因素及其挥发性风味物质消长规律的研究

以猪脂氧化产物过氧化值（POV）、茴香胺值（p-AV）和酸值（AV）为理化指标,分别考察通气量、反应温度和反应时间等氧化反应控制因素对氧化产物的指标影响,并对猪脂控制氧化条件下的挥发性风味产物的消长规律进行分析.结果表明,反应温度和反应时间是猪脂调控氧化主要影响因素.氧化过程产生的挥发性风味物质主要是醛类、醇类和酸类,...     

丙醛+正己醛含量评价DHA/ARA粉末油脂氧化情况的可行性研究

采集了DHA粉末油脂、ARA粉末油脂和ALA粉末油脂样本110个,样本涵盖了新鲜、临近货架期、超过货架期的样品,测定其过氧化值、茴香胺值、全氧化值、丙醛和正己醛含量,并将丙醛+正己醛含量与过氧化值、茴香胺值、全氧化值进行了相关性分析。Pearson相关性分析表明,丙醛+正己醛含量与过氧化值、茴香胺值、全氧化值在P0.01水平呈极显著相关,相关性系数分别为0.663、0.869和0.846;非线性拟合结果表明,丙醛+正己醛含量与过氧化值、茴香胺值、全氧化值回归方程的相关系数分别为0.726 4、0.989 0和0.978 4;测定DHA/ARA粉末油脂的挥发性丙醛+正己醛含量,将其作为特征指标可以简便、准确地表征粉末油脂的氧化情况,尤其是后期氧化情况。     

大豆热损对其油脂品质及组成的影响

旨在为热损大豆的加工提供理论支撑,以不同热损程度的巴西大豆为原料,采用索氏抽提法制备大豆油,分析其酸值、过氧化值、茴香胺值、全氧化值、氧化诱导期、甘油酯和游离脂肪酸组成及含量、磷脂及生育酚组成及含量、色素含量,探明大豆热损对其油脂品质及组成的影响。结果表明：随着大豆热损程度的增加,其油脂的酸值、过氧化值、茴香胺值、全氧化值显著升高(p<0.05),氧化诱导期显著下降(p<0.05),与正常大豆相比,重度热损大豆油脂酸值和全氧化值的增长率分别高达557%、148%;热损导致大豆油水解,甘三酯相对含量降低,甘二酯和游离脂肪酸相对含量上升,以Sn-1,3位水解为主;氧化反应导致多不饱和脂肪酸相对含量显著降低(p<0.05),且热损程度越深变化越明显;热损导致大豆油总磷脂含量下降,磷脂酸相对含量显著上升,生育酚含量降低,重度热损大豆油脂中总生育酚的损失率高达19%;未成熟大豆更易发生热损现象,不同热损程度大豆油脂中的叶绿素、叶黄素及β-胡萝卜素含量具有显著性差异(p<0.05)。综上,大豆热损会导致其油脂组成发生变化,品质降低。     

基于PCA模式不同处理方式鸡脂挥发性成分与化学指标相关性研究

分别以氧化、酶解和酶解-温和调控氧化技术对精炼鸡脂进行处理,通过GC-MS对上述不同处理方式获得的鸡脂样品中的挥发性成分进行了分析鉴定,同时对其化学指标(过氧化值、茴香胺值、酸值)进行测定;在此基础上,结合主成分分析(PCA)研究不同处理方式鸡脂挥发性成分与化学指标之间的相关性。结果表明:过氧化值表征初级氧化产物的含量,与其正相关的挥发性成分包括2-丁烯醛、β-苯丙烯醛、丁醇、(Z)-2-戊醇、1-戊烯-3-醇、1-辛烯-3-醇、(Z)-2-辛烯-1-醇、己酸乙烯基酯;与酸值正相关的挥发性成分有苯甲醛、乙醇、糠醇、柠檬烯、1-石竹烯、甲苯;茴香胺值与大部分的醛类化合物呈正相关,表征次级氧化产物的含量,包括能代表鸡肉特征风味的己醛、壬醛、(E,E)-2,4-庚二烯醛、2-己烯醛等。     

Formation of the beef flavour precursors and their correlation with chemical parameters during the controlled thermal oxidation of tallow

Thermal oxidation of tallow was assayed by peroxide value (PV), p-anisidine value (p-AV), and acid value (AV), and the volatile compounds produced at different oxidation conditions were analysed by SPME-GC/MS. The accumulation of characteristic beef flavour precursors, such as hexanal, 1-octen-3-ol, (E,E)-2,4-decadienal and (E,E)-2,4-heptadienal, reached a maximum value when heated at 140 °C for 2 h with an air flow of 75 l/h per 100 g tallow, whereas at the same temperature PV and p-AV were both at high levels, and AV was relatively low. A correlation analysis of chemical parameters and volatile compounds showed that the beef flavour precursors were positively related to PV, and the off-flavour compounds were highly correlated to AV. Therefore, a moderate oxidation of tallow could be achieved via controlled thermal treatment.     

大豆油煎炸过程理化指标与煎炸时间相关性研究

针对食用植物油煎炸过程中理化指标是否可有效反映煎炸油品品质变化这一问题,以大豆油为煎炸油,薯条和鸡排为煎炸物质进行煎炸实验。随煎炸时间延长取不同程度煎炸油检测,研究酸值、羰基值、极性组分、p-茴香胺值、过氧化值和总氧化值等理化指标与煎炸时间相关性。结果表明:所研究理化指标中酸值、羰基值和极性组分3项指标与煎炸时间相关性较好,可有效反映油品变坏程度,p-茴香胺值、过氧化值和总氧化值相关性较差。     

荤素分类煎炸对油脂品质的影响

为了延长煎炸油的使用寿命,有效降低成本,研究了荤素分类煎炸对油脂品质的影响。采用食材荤素分类及不分类煎炸并循环使用煎炸油,分析了两种煎炸方式下煎炸油的色泽、酸值、过氧化值、p-茴香胺值、极性组分含量的变化情况,并对比分析两种煎炸方式用油量。结果表明：采用荤素分类煎炸可以更好地抑制油脂色泽、酸值、p-茴香胺值及极性组分含量的增长速度;不分类煎炸油脂的色泽在煎炸2 d后无法用比色仪检测,分类煎炸7 d后油脂的色泽才接近不分类煎炸2 d的色泽;不分类煎炸的油脂酸值(KOH)在煎炸前3 d内急剧上升,由初始的0.09 mg/g增至1.30 mg/g,分类煎炸的油脂酸值(KOH)浮动较小,由初始的0.09 mg/g最高增加至0.62 mg/g;在煎炸7 d时,不分类煎炸的油脂p-茴香胺值由初始的4.0增加到38.0,分类煎炸的油脂p-茴香胺值由初始的4.0增加到15.0,不分类煎炸油脂的p-茴香胺值的增长速度是分类煎炸的近3倍;不分类煎炸,油脂极性组分含量在第1天内急剧上升,在第4天达到最高,为12.5%,后逐渐趋于平稳,分类煎炸,油脂极性组分含量在前3 d内均保持在8%左右,之后才有上升的趋势...     

白木通籽油的理化特性及热氧化稳定性

采用正己烷浸提法提取白木通籽油,对白木通籽的基本成分、白木通籽油的理化特性和热氧化稳定性进行分析研究。结果表明：白木通籽粗脂肪含量为39.33%,粗蛋白含量为17.97%;提取的白木通籽油酸价1.28mg KOH /g,过氧化值0.57mmol/kg,p-茴香胺值4.15,碘值74.12g/100g,皂化值198.6mg KOH /g;白木通籽油富含棕榈酸、油酸和亚油酸,总量高达93.73%;白木通籽油的紫外最大吸收波长为212nm,在220℃以下时热氧化稳定性较好。     

浒苔多酚协同低剂量电子束辐照对鳗鱼鲞菌落总数和油脂氧化的作用

为筛选合适的多酚预处理保护措施以减缓低剂量电子束辐照处理鳗鱼鲞中油脂的氧化酸败,延长其贮藏期,本实验对比对照（CK）、3 kGy电子束辐照、0.15%浒苔多酚（Enteromorpha prolifera polyphenols,EPP）＋3 kGy电子束辐照和0.3% EPP＋3 kGy电子束辐照4 种不同预处理措施对在4 ℃条件下贮藏6 月的鳗鱼鲞菌落总数及油脂氧化过程的影响。通过对比不同预处理后鳗鱼鲞菌落总数和油脂的硫代巴比妥酸反应物值、酸价、碘价、过氧化值、p-茴香胺值、脂肪氧合酶活力的变化,确定适合低剂量辐照鳗鱼鲞的EPP预处理方法。结果表明,低剂量电子束辐照处理促进了鳗鱼鲞的油脂氧化,EPP能有效抑制电子束处理导致的油脂劣化进程,0.3% EPP＋3 kGy电子束辐照处理能够有效减缓贮藏期间鳗鱼鲞油脂的氧化进程,并对菌落总数增长有明显的抑制作用,在整个贮藏期内,菌落总数始终不高于0.2（lg（CFU/g））,延缓了鳗鱼鲞的品质下降,延长了其货架期。     

Chemical stability of extra-virgin olive oil added with oregano essential oil

Extra virgin olive oil is highly consumed and well known for its nutritional and health benefits. However, it is fatty food highly susceptible to lipid oxidation. The objective of this study was to evaluate the preserving effect of oregano (Origanum vulgare L. spp vulgare called "oregano compacto") essential oil on physical and chemical properties in extra virgin olive oil during storage. Oregano essential oil composition was analyzed by GC-MS. This essential oil was added into extra virgin olive oil at 0.05%. The samples were stored in 3 different conditions: darkness, light exposure, and temperature (60 °C). Chemical indicators of lipid oxidation (peroxide value, p-anisidine value, conjugated dienes, free fatty acidity, and carotenoid and chlorophyll contents) were measured. High content in carvomenthol (22.52%), terpinolene (19.77%), thymol (13.51%), and γ-terpinene (10.30%) were detected in oregano essential oil. Olive oil samples without oregano essential oil stored at 60 °C and exposure at artificial light had the highest peroxide values during storage. Higher p-anisidine and K232 values after day 7 of storage were detected in temperature, darkness, and light exposure treatments. Light treatment was the main factor that degraded chlorophyll causing loss of color. The highest chlorophyll content (3.87 mg/kg) was observed in olive oil with essential oil at the end of storage. In general, olive oil samples added with oregano essential oil had lower peroxide, conjugated dienes, and p-anisidine values and higher chlorophyll and carotenoid contents during storage. Oregano essential oil retards lipid oxidation process in olive oil prolonging its shelf life. PRACTICAL APPLICATION: Oregano essential oil was and is used with the purpose of flavoring and aromatizing food. This essential oil due to its composition has shown antioxidant activity. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are thought to be promoters of carcinogenesis. Extra virgin olive oil is widely consumed because of its nutritional benefits and sensory properties which are very important to be preserved in the product. In this study, the oregano essential oil showed remarkable antioxidant activity in olive oil. Therefore, this essential oil could be considered for the industry as natural antioxidant not only to be used in olive oil but also in other fatty food products to substitute synthetic ones.     

低共熔溶剂杏仁种皮提取物对油茶籽油氧化稳定性的影响

本研究采用Rancimat法和Schaal烘箱法测定低共熔溶剂杏仁种皮提取物对油茶籽油氧化稳定性（氧化诱导时间、酸价、过氧化值和p-茴香胺值）的影响。研究结果表明：传统溶剂杏仁种皮提取物组成较复杂,低共熔溶剂在提取过程中能表现出对某种或某几种物质的选择性。添加了低共熔溶剂杏仁种皮提取物对油茶籽油酸价最大抑制量可达58.18%,明显高于传统溶剂杏仁种皮提取物。DESs2（氯化胆碱+草酸）和DESs3（氯化胆碱+苹果酸）提取物对油茶籽油的过氧化值的最大抑制量分别为83.72%和65.12%。添加DESs5（氯化胆碱+苹果酸+脯氨酸）提取物的油茶籽油p-茴香胺值升高量仅为空白组的37%。低共熔溶剂杏仁种皮提取物与传统溶剂杏仁种皮提取物相比具有更好的延长油茶籽油氧化诱导时间的效果,对延缓油脂在储藏过程中的氧化有显著效果。     

加工工艺对香榧油脂氧化和抗氧化活性的影响

研究了加工过程香榧酸价、碘价、过氧化值、p-茴香胺值、硫代巴比妥酸还原值和DPPH自由基清除能力的变化趋势,从而了解加工工艺对香榧油脂氧化和抗氧化活性的影响。结果表明,香榧在加工过程中发生了油脂的氧化酸败,其中第1次炒制和调味液浸泡后酸价和过氧化值分别较前道工序增加269.16%、56.07%和80.22%、73.17%;香榧抗氧化能力降低,表现为第1次炒制后硫代巴比妥酸还原值为前道工序的171.18%,而DPPH自由基清除能力下降至75.41%。因此,第1次炒制和调味液浸泡两道工序是影响香榧品质的重要环节。     

Antioxidant efficacy of extracts produced from pickled and dried mustard in rapeseed and peanut oils

Antioxidant efficacy of 70% ethanol extract (EE), 70% methanol extract (ME), and water extract (WE) produced from pickled and dried mustard (Brassica juncea Coss. var. foliosa Bailey) was evaluated in rapeseed and peanut oils by using the Schaal oven method. The protective effects of aforesaid 3 extracts in stabilizing vegetable oils were tested by measuring their peroxide values, conjugated diene values, and p-anisidine values during storage of 15 d at 60 °C. Results showed that the different solvent extracts produced from pickled and dried mustard, at concentrations of 0.5% and 1.0% (w/w) in vegetable oils, could significantly (P < 0.05) lower the peroxide value, conjugated diene value, and p-anisidine value of oils during storage at 60 °C. However, the extracts at various concentrations showed a less antioxidant effect than butylated hydroxytoluene (BHT) at 200 ppm. The ultraviolet spectra of different extracts exhibited a single maximum absorbance at 268 nm. The qualitative analysis of antioxidants present in the extracts was carried out by reverse phase high performance liquid chromatography (HPLC) using a C18 column. Two phenolic compounds, gallic and protocatechuric acids, were identified. The antioxidant activity of the extracts might be attributed to the presence of these phenolics. These results indicated that the pickled and dried mustard could be used as a potential source of natural antioxidants. PRACTICAL APPLICATION: The antioxidant activity of extracts produced from pickled and dried mustard toward rapeseed and peanut oils oxidation and the characterization of active phenolic compounds may be useful in developing natural antioxidants for vegetable oils. Moreover, the extracts could safely be used as potential antioxidant to suppress lipid oxidation in lipid-containing food products.